Hi All, I'd greatly appreciate your assistance!

A friend and I are planning a trip to Colorado to do some climbing/hiking (mostly for endurance training), and we're trying to figure out expected weather. We're looking at the Mt. Democrat/Lincoln/Bross traverse. We're probably going to end up in the middle to end of September. Can anyone advise on what kind of weather we can expect at that point? We're more than comfortable with crampons/ice axes, so absolutely trying to understand whether we could expect snow, or enough snow to need technical gear. In addition, general thoughts on temperature that time of year (especially on top of a 14'er with wind) we could expect.

For reference, we live on the east coast but have done summer hikes/climbs in the White Mountains (Northeast) and summer alpine climbs in the Cascades.

Thanks!

I've done several September climbs in Colorado and for climbs like the Decalibron you're not going to need crampons or ice axes. Microspikes could be helpful on the descent from Bross if there has been snowfall but you're more likely to carry them and not use them. If you're doing something steep in RMNP obviously that would change but for any Class 1 or 2 route sans exposure you should be fine with non technical gear. 14's in Colorado are somewhat similar to hiking in the Presidentials in September; the weather could go to hell so rain pants and a top are an absolute must, along with at least a fleece, gloves and a hat. Wind can be harsh, but it's not as bad as the Presidentials. The main difference between the two is actually distance above tree line, so when thunderstorms threaten in Colorado, you have more distance to cover before getting to tree line, especially on Decalibron. On the plus side, by September the thunderstorms are no longer the routine afternoon occurrence they were a month ago, but snowstorms with serious snowfall are much more common, especially towards the end of the month. I got snowed off of Blanca in September of 2011 because I was inadequately equipped for the conditions, which led to me finally buying some gear I had put off buying for some time while I was climbing almost exclusively in the Northeast and Southeast. The fact that you've done summer alpine climbs in the Cascades means this will not be a big transition.

Thanks! This is mostly in line with what I expected, though the part about lesser chance of thunderstorms in the afternoon is good news.
We can pretty easily plan for deteriorating conditions. Snow and cold is fine (hope for it, actually). But when it snows, what can we expect from the route up and through and down? As this is our first time out there, just thinking about route finding conditions and such.

It is usually nice is September, but it can and does snow, sometimes (though rarely) more than a few feet.

The only way to know is to check right before your trip.

Lincoln, Democrat, and Bross are some of the easiest 14ers to climb and any day of the year, so I wouldn't worry too much.

It is extremely unlikely that the snow will be consolidated enough to use an ice axe even if it does snow. Except for a few late summer/early fall alpine ice/snow climbs (which don't exist on those peaks you list), micro spikes are usually a much better option in September than ice axe and crampons.

After Labor day weekend is a great time to to hike the 14ers. There are less people in the mountains. However, since these are so close to Denver there still will be a fair amount of people hiking them. If you can avoid hiking them on the weekends, that would be ideal.

September is usually a great time to hike 14ers, unless we have had an early big storm. I have never needed 'spikes or an ax since the snow, if present, is rarely icy. Be prepared for cold and wind. Also, don't use word "traverse" for the Decalibron stroll. In Colorado that term is typically reserved for the four Classic Traverses of El Diente-Wilson, Maroon Bells, Little Bear-Blanca, and the Crestones.